Database - The Relational Model and Normalization - Discussion

Discussion Forum : The Relational Model and Normalization - General Questions (Q.No. 14)
14.
A key:
must always be composed of two or more columns.
can only be one column.
identifies a row.
identifies a column.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
16 comments Page 2 of 2.

Roja iza said:   1 decade ago
A key column is one that uniquely identifies a particular row in the table.

Hudson exaud said:   1 decade ago
Correct answer is D.

A key is the one that uniquely identify a column in relation.
(1)

Krishna said:   10 years ago
A key is definitely a constraint which is applied on the column which helps column to have a unique value, but each value in a column is row. Hence key identifies a row.

Garg said:   9 years ago
From key we get result as row not as coloum hence, key defines a row. Please refer definition of key.

Tripti said:   5 years ago
A DBMS key is an attribute or set of an attribute which helps you to identify a row (tuple) in a relation(table). They allow you to find the relation between two tables. Keys help you uniquely identify a row in a table by a combination of one or more columns in that table.

Tripti said:   5 years ago
Key extract data from a table, it is a set of attributes which can uniquely identify a row or a tuple from a table.


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